Yumiko Abe , better known by her ring name Yumi Ohka , is a Japanese professional wrestler. Originally trained by the now defunct JDStar promotion, Ohka now works for Oz Academy and Pro Wrestling Wave. She is a former two-time Wave Single Champion, while also being a former Oz Academy Tag Team Champion and Wave Tag Team Champion. She is the managing director of Zabun Co., Ltd., which owns Pro Wrestling Wave.

The Wave Single Championship is a women's professional wrestling championship owned by the Pro Wrestling Wave promotion. The title is nicknamed and more commonly referred to as the Regina di Wave Championship . The championship, which is situated at the top of Pro Wrestling Wave's championship hierarchy, was first announced on December 5, 2012. The inaugural champion was crowned on March 17, 2013, when Yumi Ohka defeated Kana in the finals of a five-woman tournament.